Olivia Thirlby (JUNO) has joined the cast of Summit and New Regency's sci-fi flick, THE DARKEST HOUR, reports HEAT VISION. Chris Gorak is the director with Timur Bekmambetov and Tom Jacobson producing.

Written by Gorak and Josh Zetumer, the Moscow-set story centers on an American traveling group who getting wrapped up in an alien invasion. Thirlby will play a rich girl trying to survive with her fellow travelers.

Production will take place in Moscow this summer.

Summit is will distribute in the U.S. with Fox taking international sales.

Regency's SVP production Navid McIlhargey is shepherding with Summit president of production Erik Feig and Summit svp acquisitions and co-productions Michael Schaefer doing the same for their firm.